[greenhead05]

I drive a 1998 K1500 with 100,000 miles. I have noticed lately that my truck has absolutely no power. It almost seems to bogg down. Every now and then when I put high octance fuel in my truck it runs great and has very good power. Then when I go back to the cheap stuff the power is lost. Could this be that my computer is reading the fuel measurements wrong, or the air to fuel ratios aren't right, timing problem, or what? I have replaced the fuel pump, fuel filter, air filter, change oil regularly, fuel relay, plugs, distributor, and rotor. I also ran a diagnostics test on the truck to see if it was throwing any codes and it wasn't. There should be more power to my 350 V8 than what I am experiencing. What other reasons could it be that I don't have the power that I should have?